The present invention relates to a polymeric membrane having maleic anhydride residues, an ion exchange membrane derived from the membrane, and an enzyme immobilizing membrane.
The maleic anhydride copolymer is known as a reactive polymer because the maleic anhydride residues are reactive. The maleic anhydride copolymer, however, has not been put into practical use in the form of membrane because it hydrolyzes gradually in an aqueous solution into a water-soluble polymer of high electric charge density and it considerably swells in water and increases in stickiness, with the resulting difficulty in handling, even when it is cross-linked with a bifunctional cross-linking reagent.
In order to develop a polymeric membrane derived from maleic anhydride copolymer which can be used practically in an aqueous solution, the present inventor carried out a series of intensive studies, which led to the findings that the maleic anhydride copolymer becomes insoluble in water and swells only a little in water when it is blended with a support polymer and then partially cross-linked with a bifunctional cross-linking reagent. The present invention is based on these findings.